typedef UInt32 IOStreamBufferID;  

struct IOStreamBufferQueue { 
    UInt32 entryCount; 
    volatile UInt32 headIndex; 
    volatile UInt32 tailIndex; 
    UInt32 reserved; 
    IOStreamBufferQueueEntry queue[0]; 
};  

struct IOStreamBufferQueueEntry { 
    IOStreamBufferID bufferID; 
    UInt32 dataOffset; 
    UInt32 dataLength; 
    UInt32 controlOffset; 
    UInt32 controlLength; 
    UInt32 reserved[3]; 
};  

enum { 
    kIOStreamOptionOpenExclusive = 0x00010000, 
    kIOStreamOptionOpenShared = 0x00020000 
};  

enum { 
    kIOStreamPortTypeOutput, 
    kIOStreamPortTypeInput 
};  

enum { 
    kIOStreamMemoryTypeOutputQueue = 0x10000000, 
    kIOStreamMemoryTypeInputQueue = 0x20000000, 
    kIOStreamMemoryTypeBufferData = 0x30000000, 
    kIOStreamMemoryTypeBufferControl = 0x40000000, 
    kIOStreamBufferIDMask = 0x0FFFFFFF, 
    kIOStreamMemoryTypeMask = 0xF0000000 
};  

enum { 
    kIOStreamMethodOpen, 
    kIOStreamMethodClose, 
    kIOStreamMethodStart, 
    kIOStreamMethodStop, 
    kIOStreamMethodSuspend, 
    kIOStreamMethodGetMode, 
    kIOStreamMethodSetMode, 
    kIOStreamMethodGetBufferCount 
};  

enum { 
    kIOStreamEnqueueInputTrap, 
    kIOStreamEnqueueInputSyncTrap 
};